Effective math tool

acethecase calculations Case cheng consulting math percentage
New answer on Aug 31, 2020
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Anonymous A asked on Sep 12, 2018

Hello! I am looking for an effective math tool to improve my math. I am already using the free math tool from Cheng's website (the free one) and the one on preplounge. I heard about Fastmath Ace the case and the Cheng one you have to pay for. Any suggestions, reccomandations?

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replied on Sep 12, 2018
McKinsey / Accenture Alum / Got all BIG3 offers / Harvard Business School


Any of these tools are good: Preplounge Mental Math, V. Cheng, Mimir Math.

It's more about the skills. I recommend to concentrate on the following:

1) Learn how to multiply double digit numbers (https://www.youtube.com/watch?v=6ndkkPZYJHo).

2) Learn how to work with zeros. You've mentioned - always use 10^power instead of zeros


300x9000 = 3*10ˆ2 x 9*10ˆ3=3x9*10ˆ(2+3)=27*10ˆ5

Handwritten it looks not that complicated. If you get used to writing all the numbers that way, you will never loose zeros and all multiplications/divisions will be replaced with + or -.

3) Learn the division table up to 1/11 (i.e. 5/6 = 83.3%). It will help you calculate any percentage problems

Good luck!

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Ornella on Sep 13, 2018

Thank you very much for this Vlad. Do you know any tool to practice these kind of calculations and where can I find the division table?

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replied on Aug 31, 2020
McKinsey | top 10 FT MBA professor for consulting interviews | 6+ years of coaching
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replied on Sep 12, 2018
Collected McKinsey & BCG offers/ Ex-McKinsey consultant/Harvard/WBS/MSU

Hi A,

The best one I used for my preparation and the one I suggest for my students is Mental Math.
It has 3 advantages

  1. You choose level of difficulty
  2. You practice the weakest part of your math (e.g. multiplication)
  3. You may read useful tips, while practicing

Furthermore, it teaches you problem-solving: multiplication problems are shown to be solvable by breaking problems down into medium and easy level problems.

The link is below:

All the best,


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Anonymous replied on Aug 22, 2020

Dear A!

You can try 'Case Math' on the iOS store.


Magoosh's mental maths app, Mental math cards challenge app would be also useful.

In general, to practice your quantitative skills I would recommend different math, logic, and verbal tests on https://trytalentq.com/how-to-prepare/# and then select "Elements Practice Test".

You don´t need to learn them by heart, rather skipping through to get a first impression and a better understanding.

If you need any further help or career advice, feel free to reach me out.



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Anonymous B replied on Oct 21, 2019

There is just one thing: practice, practice, practice, ...

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Vlad gave the best answer


McKinsey / Accenture Alum / Got all BIG3 offers / Harvard Business School
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